There will often be multi-type business processing work in enterprise application development, and a good design method will bring great benefits to applications and maintenance, and we start from a simple case.
A book sales system is handled in customer payment:
Classification: Ordinary consumers, general members, VIP members, other types of pending.
Treatment requirements: ordinary consumers do not enjoy discounts
General members enjoy 15% discount
VIP members enjoy 20% discount, plus accumulated points
Other types to be determined
Let's implement it below. When we implement, most people think of writing a method (function) to the settlement operation, we will write this way in the function:
String ls_customer_type
Double LD_Payment
// Cancer type
LS_CUSTOMER_TYPE = ............
IF ls_customer_type = 'g' Then // General consumer
// processing process
Elseif Ls_Customer = 'V' // VIP Consumer
// processing process
Elseif
.....
END IF
// Other processing
Return LD_PAYMENT
Or use the Choose Case instead of the IF ELSEIF statement, the structure is tilted.
Such treatment methods are not very convenient for increased, reading, and new types of new types. If every type of processing has a lot of line code (dozens of lines to the hundred lines), everyone is more difficult to read, add a new type, you need to modify the method, the code will be longer, each processing The variables used are also very prone to cross, and the program is faulty is difficult.
In the face of the above questions, my design method is to create a method separately for each type, providing an identical interface, and a method requires a method to receive requests and return results. In this way, whether it is clear when debugging or running, a method corresponds to a process, increasing a new type, adding a method does not need to modify other method content, and the program is relatively relaxed.
Specific design implementation:
Create a settlement processing object: UO_BALANCE
Balance's method: of_getpayment (as_customer_type) // External Access Processing
OF_GETGENERALPAYMENT () // ordinary customer settlement processing
OF_GETVIPPAYMENT () // VIP member settlement processing
Of_otherpayment () // Other Processing
OF_GETPAYMENT method implementation:
